The present invention relates to a method of disposing of a waste optical disc for collecting a substrate material from an optical disc treated as waste.
Optical discs, if physically classified, are roughly divided into read-only discs, write-once discs and rewritable discs. A CD known as one of the read-only discs is configured in such a manner that a reflective layer and a protective layer are laminated in order on a substrate layer. Also, a CD-R known as one of the write-once discs is configured in such a manner that a recording layer, a reflective layer and a protective layer are laminated in order on a substrate layer. Further, a CD-RW known as one of the rewritable discs is configured in such a manner that a dielectric layer, a recording layer, a dielectric layer, a reflective layer and a protective layer are laminated in order on a substrate layer.
Every existent optical disc is provided with a substrate layer mainly composed of the optical disc. The substrate layer is formed of a material pervious to a laser beam for data reproducing or date recording, for example, such as polycarbonate resin, acryl resin, polyolefin system resin, epoxy resin, glass or the like.
Now, concerning the aforesaid optical discs, as their demand increases, a waste disposal thereof becomes a problem. By the way, the optical discs treated as waste include discs damaged in the middle of a production, discs treated as defective at a final inspection process after the production, discs treated as surplus stock or the like.
Up until now, a method for burying trituration of the waste optical disc or a method for incinerating the waste optical disc has been adapted as a disposal method for the waste optical disc. However, in case of the former disposal method, it is difficult to select a burying ground and in case of the latter disposal method, there is a problem that a special incinerator is required. There is no saying that any of these disposal methods is undesirable in view of environmental conservation.
In view of the aforesaid situation, recently a method for collecting a substrate material by chemically removing a layer portion other than a substrate layer from a waste optical disc has been proposed. (For example, Japanese Patent No. 2615277 or Japanese Patent Laid-Open No. 8-164524.) However, the disposal methods as described in these official gazettes have a problem in that a range of applications is reduced at the time of recycling the substrate material, because a chemical material change to the substrate material comprising polycarbonate resin or the like in a disposal process and it is difficult to secure an expected quality of the collected substrate material.
An object of the present invention is to provide a disposal method of the waste disc collectable from the optical disc treated as waste without causing any material change to the substrate material.
A disposal method of a waste optical disc having at least one other layer on a substrate layer, comprises the steps of creating a space between layers by giving an external force to the disc, and peeling off at least one of the other layers from the disc by making gas invade into a space. According to this disposal method, by giving the external force to the disc so as to create the space between the layers, and by making a gas such as air or the like invade into this space, at least one of other layers can be peeled off and easily removed.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description and the accompanying drawings.